1. Field of the Invention
The present invention relates to magnetic based sensors and particularly to low switching current non-volatile magnetic based memory.
2. Description of the Prior Art
Computers conventionally use various media for data storage. Prevalent media include rotating magnetic media, such as hard disk drives (HDDs) for non-volatile storage, or dynamic random access memory (DRAM) and static RAM (SRAM), which are volatile and very costly but have fast random read/write access time. Solid state storage, such as solid-state-nonvolatile-memory (SSNVM) devices having memory structures made of NOR/NAND-based Flash memory, providing fast access time, increased input/output (IOP) speed, decreased power dissipation and physical size and increased reliability but at a higher cost.
There has been an extensive effort in development of Magnetic RAM (MRAM) as an alternative to existing data storage technologies. One of the problems with prior art memory structures is that the current and power requirements are too high to make a functional memory device or cell. This also poses a key concern regarding the reliability of such devices due to likely dielectric breakdown of the tunneling barrier layer and thereby making it non-functional.
The challenge with other prior art techniques has been that the switching current is too high to allow the making of a functional device for memory applications due to the memory's high power consumption. The high switching current is due, at least partly, to the memory element's electrical resistance. Several current solutions suggest that the switching current can be reduced by having the memory element pinned by two anti-ferromagnetic (AF)-couple layers resulting in spin oscillations or “pumping” and thereby reducing the switching current. Although these methods are helpful in reducing the memory element's resistance, further improvements in reducing the resistance of magnetic memory devices is desirable.
One prior art technique disclosed a structure and process for reducing switching current by including a fixed layer, a barrier layer formed on top of the fixed layer, a first free layer formed on top of the barrier layer, a non-uniform switching layer (NSL) formed on top of the first free layer, and a second free layer formed on top of the non-uniform switching layer. In the foregoing, switching current was applied, in a direction substantially perpendicular to the fixed, barrier, first free, non-uniform and the second free layers causing switching between states of the first, second free and non-uniform layers with substantially reduced switching current. Although switching current is reduced, there is still a need for further reduction in switching current.
What is needed is magnetic memory with lower resistance, thus further reducing power consumption associated with reading and switching data bits.